New Fox 35 Stunt vs OS LA40CL for ARF Nobler

Hello, all. I haven't flown a c/l model in about 35 years and was thinking of getting the Nobler. I am trying to decide between these two engines. I am curious if the LA40 will 4-2-4 cycle like the Fox's do?
I have heard that it will, and some say they don't. Really like the way the old Fox's run. Any input would be appreciated.
Thanks
Alan Young

We could spend all day of this question. To make it short Yes, No, and Maybe.
Yes..If you spend the time to learn how to run the engine
No...If you don't learn hoe to run the engine.
Maybe. Run the engine just the way you would run a fox.

Break it in correctly
Do not over prop.
Use the right fuel, plug.

Remember the LA is made to run at a higher RPM'S then the Cross Flow Fox .35.

But sure you can do it.

Scott(r-u confused yet)Riese

>Hello, all. I haven't flown a c/l model in about 35 years
>and was thinking of getting the Nobler. I am trying to
>decide between these two engines. I am curious if the LA40
>will 4-2-4 cycle like the Fox's do?
>I have heard that it will, and some say they don't. Really
>like the way the old Fox's run. Any input would be
>appreciated.
>Thanks
>Alan Young

Alan, if you run the LA40 like the Fox, you won't get the power out of it that it is capable of producing. If you are thinking of getting an ARF Nobler, which are quite light, and if you don't fly it in a lot of wind and are not competition minded, and if you like the way the Foxes run because that is what they did 35 years ago (and it sounds like a "yes" up to this point--except for the wind. Say, "Yes" to not flying in heavy wind!) well, then put in the Fox. The Fox will have enough power for the plane to do what you want. If you try to make an engine run and sound like a Fox, well, you are only going to get the power of a Fox out of it anyway.

I got an FP 40 from one of the well known engine tuners right after these engines came out. It was a wimp. Very weak. When I consulted with the engine tuner who had done the modifications, he said it was made to run like a Fox. Well, I had to grant him that. It ran like a Fox. It sounded like a Fox. And it had the power of a Fox. It taught me something. Why buy this engine, then spend your extra money to modify it, if it is going to run like a...? Why not just buy a Fox in the first place?

If that is the way you want it to run, then get the engine that runs that way. It is probably one of the weakest 35 size engines out there, but it will pull your airplane fine for what you probably want it to do.

Thanks very much for the replies. I do like the way the Fox does it's 4 cycle 2 cycle thing. I remember having an OS 35 on a Ringmaster that you couldn't practically slow it down. Basically just a wide open type of running. Replaced it with a Fox 35 Stunt and enjoyed flying the thing a whole lot more. Thanks again for the info!

Alan Young

LAST EDITED ON Dec-11-03 AT 11:51 PM (CST)
 
Alan:
The OS LA 40 is a good motor if run right, the draw back is it weighs 2.6oz more than a Fox, most likely you would add tail weight to compensate increasing the weight even more. I've seen two ARF Nobles powered with Fox 35's fly very well.
Another very good choice is the Brodak 40 if you can get one.

Larry Foster

>Alan:
>The OS LA 40 is a good motor if run right, the draw back is
>it weighs 2.6oz more than a Fox, most likely you would add
>tail weight to compensate increasing the weight even more.
>I've seen two ARF Nobles powered with Fox 35's fly very
>well.
>Another very good choice is the Brodak 40 if you can get
>one.
>
>Larry Foster

I wouldnt recommend the Fox even if you have used them in the past. We have come a long way since the design of the fox motors. They are very weak compared to moderm motors. I would opt for the Brodak 40 if you want a 4-2 break but with much more power and a really nice (AAC) motor. In fact I would go with the OS 25 LA over the Fox any day (just ask Brett about his Skyrays). I have never had much success with the Fox 35- tempermental, low power, requires all castor fuel, really not the best option IMHO. And as Len says, if the wind comes up you will wish you had something stronger...

>I wouldnt recommend the Fox even if you have used them in
>the past. We have come a long way since the design of the
>fox motors. They are very weak compared to moderm motors. I
>would opt for the Brodak 40 if you want a 4-2 break but with
>much more power and a really nice (AAC) motor. In fact I
>would go with the OS 25 LA over the Fox any day (just ask
>Brett about his Skyrays). I have never had much success with
>the Fox 35- tempermental, low power, requires all castor
>fuel, really not the best option IMHO. And as Len says, if
>the wind comes up you will wish you had something
>stronger...

I’ve had a LA 25 on a Ringmaster, took it off and went back to the Fox. I’ve had several people purchase motors from me to replace the LA 25.
I'll put one of my motors, Lew Woo lards or Randy Smiths or just a plain good Fox 35 against an LA 25 any time. The LA25 has a problem swinging a 10X4 with out sagging unless the weather is just right or your at sea level. It just doesn't have the authority. The LA 25 just doesn't have the power of the Fox 35 haven’t seen it yet. Enuf said I won't get pulled into one of these pointless debates with a guy how can't even put his profile up there so people will know who he is.

Larry

I had planned to use a Fox in my Nobler ARF, but took the advice of a very experianced flier and went with the LA40. I used a tongue muffler, metal backplate and standard needle valve, and after reinforcing the nose, and beefing up the tail a bit for stooge launching, mine balanced almost perfectly. If I had used a Fox, the plane would have been tail heavy. I guess weight and balance depends on the individual kit. Anyway, I like the .40LA on my airplane.

Don:
If I knew that the OS40 had no balance problems then I would highly recommended it. It’s a good motor; I wouldn’t rework them if I didn’t think they were. The earlier 40’s had a lighter crankshaft in them then the current production. The Fox 35 is a challenge that’s why I rework it and some other reasons. I know of one ARF Nobler that had to add tail weight to balance and the plane and had trouble in hotter air. I lightened that motor up 7/10ths of an ounce on the mill and had him remove the spinner; it helped a lot but still had problems drifting down in the corner in hot air. I personally don't think you can go wrong with the OS LA40 if the balance is good without adding weight, the Brodak 40 is an excellent choice for it’s price, or a reworked Fox 35 but it’s twice the price of the OS LA40 or a good Fox 35. I do believe the OS LA25 is a very bad move as bhadley0 recommend. The only thing he did have a good point on is fuel availability for the Fox 35 is a problem.

Larry

>In fact I
>would go with the OS 25 LA over the Fox any day (just ask
>Brett about his Skyrays).

I am not convinced that the 25LA is quite the same as a 20 or 25FP, or a Fox. I do know that for this size model the 20FP will blow the Fox out of the water, having tried the direct substitution. But I haven't tried it with the LA, and I haven't been excessively impressed with the LA's power just watching from the outside.

My understanding is that the LA has the boost port blocked, or doesn't have one, or something like that. This would greatly reduce the power capability, and it may require different props than the FP for maximum performance. I may have, in the past, not made a distinction between the FP and LA - but if so, that was wrong.

Actually, there are people that fly Fox 35s competitively and do quite well. I believe Kenny Stevens won the 2002 NATS Advanced class with a Fox 35 powered Cavalier. Marvin Denny (Bigiron) is always competitive with his Fox powered Novi models.

Len, if you remember the winds at the Peoria contest this Fall were not very friendly. Advanced class was won with a Fox 35 powered plane (mine). Admittedly, I had to compensate dramatically at times (especially flying on the Beg/Int circle for the 2nd round), but so did many Expert fliers using contemporary power plants. I believe it's not the characteristics of the Fox, but rather matching it's capabilities with the right airplane. Marvin Denny has certainly achieved that match with every Fox powered plane I've seen him fly.

So, don't be afraid of the Fox 35 in a Nobler. Remember all the contests GMA won with that combination! In a full-fuselage configuration, those dreaded (profile-mount) Fox characteristics vanish, leaving a very predictable, reproducible 4-2 run.

Fred

I think you should pick an engine to make your airplane fly the way you enjoy flying. Do you want to fly slow, do you want to fly fast, or do you want to fly somewhere in between?

When I was a boy we fly as hard and fast as the airplanes would go. Thats the way we all flew then. Now days everone flies much slower.

I stopped flying for 35 years and got back into flying again about 4 years ago. I have experemented with several engines and several airplanes. Everytime I go flying I take a box of engines, a box of props and several airplanes. 3 weeks ago we had 20 mph wind, I was determined to fly that day so I flew with the OS Max 40 LA engine with an 11x6 prop on my Nobler and I put an OS Max 25 LA with an 9x6 prop on my Sterling Ringmaster. Last week the wind was calm so I put a Fox 36X on the Nobler and a McCoy 35 on the Ringmaster both engines had a 10x6 prop. The Nobler flew great. I changed the prop to 11x5 on the Fox 36X and the next flight was even better. Its a toss up between the Fox 35 and the McCoy 35 engine. McCoy is 1 ounce heaver than the Fox so if your airplane is tail heavy use the McCoy 35 engine.

The OS Max engines are higher RPM engines that the older Fox and McCoy engines. You can make the engines do basically the same thing by changing the diameter and pitch of the prop. A Fox 35 or McCoy 35 will fly about 55 to 60 mph with a 10x6 prop. A Fox 36X will fly about 65 mph with a 10x6 prop. The OS Max 25 LA will fly 75 mph with a 9x6 prop, 90 mph with an 8x8 prop, about 55 mph with a 10x4 prop. The OS Max 40 LA will fly 70 mph with a 10x6 prop you can needle the speed down to about 55 mph. More prop diameter gives you more power and more prop pitch gives you more speed.

You need to experement to find what you like. Sometimes I like to fly like we did when I was boy and other times I like to fly slow. The other day I put the OS Max 25 LA with a 8x8 pitch prop on my Sterling Ringmaster and flew it 90 mph. After about the 10th lap I was wishing it would hurry up and run out of fuel. I really don't like to fly over 75 mph and the more I fly the more I like flying slow. I am starting to like flying more in the range of 55 to 60 mph. Sometimes it fun to fly like we did when I was a boy with the old airplanes and the old engines it brings back memories.

Larry: Don't know about the OS 25 LA, but the OS 25 FP goes nose to nose with a Fox Stunt 35. I fly these motors, one after another (albeit on different models), all the time. Lap times, pull, maneuver authority, subjective feel, all of this make these venerable mills very close in performance.

But they accomplish their tasks in different ways. The Fox likes a 10-5 or 10-6, shakes, and is relatively loud, even with its factory muffler (which, admittedly, I open up a bit, full disclosure here). The OS is silkly smooth and quiet, and likes a B Y and O 10-4.

By the way, someone mentioned here recently (or maybe Flightlines), re Foxberg Racing, that their club allows OS 25 FPs (and maybe LAs) right along with the Foxes, since the lap times are equivalent!

Alan: I am not trying to talk you out of the Nobler at all, but, due to the long layoff, have you considered the ARF Flite Streak instead? This could be a more prudent choice.

I agree with the FP25 but the LA25 was the one the guys with no name recommend, I think it bad advise.

Larry

I watched one of the local guys fly his new Brodak Nobler for the first time last week with a L&J Fox. Perfect! Flys just the way it was supposed to with plenty of power an a great 4-2 break. There's something special about watching an OTS airplane fly well with an OTS engine. There have been some comments about difficulty running the Fox. I haven't had nor seen that problem. All the castor is a problem to clean up, but other than that, it is similar to later bushing engines to operate. As for power, the Fox (at least with Larry's rework) puts out about the same power as the Brodak 40. So far, it is also easier to get a good needle valve setting on the Fox than the Brodak.
Steve